First jamming session

So it happened and i really enjoyed it. One question though the guiarist i was playing with said play one of the songs in drop d then you can play it on the same string, Can anyone explain this, I presume the E string was droped down to a D note but why do people do this

In general, the lowest chord you can get on a guitar is an E. If you tune the E string down to a D, you can extend your low range. A lot of grunge does this, it's just for improving your pitch range on the instrument. However, I have to say, most people who do this have no idea what they are doing and just do it for no better reason than that it makes them cool.